EEL 4511 Dr. Gugel LAST NAME FIRST NAME Spring 2016, Real-time DSP Exam #1

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1 EEL 4511 Dr. Gugel LAST NAME FIRST NAME Spring 2016, Real-time DSP Exam #1 Open book and open notes, 60 minute examination, No electronic devices are permitted. Page 1 36 points Page 2 24 points Page 3 24 points Page 4 16 points TOTAL out of 100 For the following problems, consult the LIST file in the Appendix to answer the following questions. 1. What is the effective address for the instruction MOV AH,0x4ABC (line 13)? Hex (3 pt.) 2. At run/execution time, what is the value of the operand in MOV AR0,#value1 (line 17)? Hex (3 pt.) 3. What is the effective address for the instruction MOV AL,*AR0 at run time (line 18)? Hex (3 pt.) 4. What value is the Stack Pointer being initialized to? Hex (3 pt.) 5. What is the value of the SP & stack memory contents upon execution of MOV AH,#0x0 (line #36)? (6 pt.) SP = Hex Stack Memory Address & Contents Below Addr (Hex) Data (Hex) 6. What is the value of the SP after the POP AR0 (line 53 is executed)? Hex (3 pt.) 7. At load time, what addresses in DSP memory will be modified? (3 pt.) 8. At run time, what addresses in DSP memory will be modified? (3 pt.) 9. What is the final computed result stored in value3 after MOV *AR0,AL (line 27) is executed? Hex (3 pt.) 10. What does SUB1 compute? i.e. It approximately computes... (3 pt.) 11. What is the largest unsigned input value we can pass via AL to SUB1 before that will not result in a 16 bit unsigned overflow result? i.e. The answer will still fit in 16 bits. (3 pt.)

2 12. Assuming that the DSP has an internal 16 bit data bus and 22 bit address bus, fill out the following cycle execution table for execution of the two instructions listed below. Write all values in Hex. (10 pt.) line #17 MOV AR0, #value1 ; 2 cycles for instruction execution line #18 MOV AL,*AR0 ; 2 cycles for instruction execution Cycle# R/W PC (Hex) A15:0 (Hex) D15:0 (Hex) Reg Driving the Addr Bus Device Driving the Data Bus 1 R A student would like to use our DSP to interface the following continuous memory block: 128K x 16 starting at address Hex using 64Kx16 SRAMs. Show connections required for the SRAMs and corresponding Decode circuitry. Label all signals and assume FULL ADDRESS DECODING. (10 pt.) 15. To reduce the physical wiring in the above problem #14 decode circuitry, if the least significant address line used in the above decode circuit is removed and left open, what will is the new range be for each SRAM? (4 pt) Page 2 Page Score =

3 16. SRAM/CPLD Timing Problem (8 pt.) Using the DSP timing diagram and the specifications below. Determine the range of propagation delay required for the CPLD that will be used in problem's 14 and 15. DSP Specifications & Requirements WRITE Cycle -xcs width = 80 nsec -xcs true to -WR true = 15 nsec -WR width = 50 nsec Data Setup before -WR false = 15 min/ no max nsec Data Hold after -WR false = 5 nsec SRAM Specifications & Requirements WRITE Cycle -CE width = 25 min/no max nsec Data setup on -CE or -WR false = 8 min/no max nsec Data hold on -CE false = 3 nsec DSP Specifications & Requirements READ Cycle xcs width = 80 nsec -xcs true to -RD true = 15 nsec -RD width = 50 nsec Data Setup before -RD false = 7 min/no maximum nsec Data Hold after -RD false = 5 min/30 maximum nsec SRAM Specifications & Requirements READ Cycle -CE width = 25 min/no max nsec Memory Access time from -WR false AND -OE true AND -CE true = 25 nsec Data hold on -CE or -WR false = 12 min/14 max nsec CPLD Propagation Range to nsec 17. A vector contains (256) 16-Bit UN-Signed Numbers. Write code to compute the average value for the vector. Use the variables listed below in your solution. The best solution will receive the highest points. You are not allowed to use any 32 bit MOV or 32 bit ADD instructions. Use AR0 as a pointer to the data and AR1 as a counter. (16 pt.) Hint: To perform the required division, see the attached 'Shift Operation' attached data page. LENGTH.word 256 ;vector length (64 bit LSR/LSL instructions handed out at test) VEC_START_ADDR.word 0x8000 ;vector starting address FINAL_ANS.word 0x400 ;where your final answer should go Page 3 Page Score =

4 18. A student is being passed a radius value on GPIO31:0 as a standard IEEE floating pt. number in the same format at that used for 32 bit floats on our DSP. Write the FPU code to compute to compute the Area of a circle of this radius where Area = Pi*(radius^2). Then convert this result back to a 16 bit unsigned integer which then should be written back to GPIO 47:32. Assume all the necessary GPIO bits are already initialized. (16 pt.) Hint: To perform the required division, see the attached 'Shift Operation' attached data page. Pi.float !!!ALL CODE BELOW SHOULD BE IN ASSEMBLY!!!! Page 4 Page Score =

5 Appendix. Typical DSP Assembly Program 1.global _c_int00 2 A000 data_section.set 0xA data ;section starts at 0xA000 in Linker Command File value1.word 0x value2.word 0x value3.word text ;section starts at 0x9000 in Linker Command File _c_int00: A9 MOV AL,#0xCCCC ;used to test flags for demo in class, ignore CCCC A8 MOV AH,#0x4ABC ;class demo purposes ABC A8 CMP AL,AH ;class demo purposes A8 ADD AL,AH ;class demo purposes A0" MOV AR0,#value1 ;SIMPLE PROGRAM STARTs Here for Questions C0 MOV AL,*AR AA0 INC AR a 96C0 MOV *AR0,AL b 28C0 MOV *AR0,#0x c d 28AD MOV SP,#data_section+0x e A f 28A0" MOV AR0,#value C0 MOV AL,*AR ' LC SUB1 ;subroutine I/O passed through AL C0 MOV *AR0,AL F00 END1: B END1,UNC SUB1: ;AL has input value & passes back output result 32 ;Helpful Info: 1/8 = 0.125, 1/16 = , 1/32 = , 1/64 = A0 PUSH AR0 ;protect registers modified by subroutine A8 PUSH AH B00 MOV AH,#0x A0 MOV AR0,AL a FFC2 LSR AL, b 95A9 ADD AH,AL c 92A0 MOV AL,AR d FFC5 LSR AL, e 95A9 ADD AH,AL f 92A0 MOV AL,AR A9 ADD AH,AL A9 ADD AH,AL A9 ADD AH,AL A8 MOV AL,AH AA8 POP AH AA0 POP AR LRET Page 5 Page Score =

EEL 4511 Dr. Gugel LAST NAME FIRST NAME Fall 2015, Real-time DSP Exam #1

EEL 4511 Dr. Gugel LAST NAME FIRST NAME Fall 2015, Real-time DSP Exam #1 Open book and open notes, 60 minute examination, No electronic devices are permitted. Page 1 33 points Page 2 17 points Page 3 10